Tuesday, 18 February 2014

What is Enzyme Modified Cheese?

Enzyme modified cheese or EMC as they are known are a cost effective alternative to natural cheeses. They are produced using enzymes on the cheese curds or immature cheeses to produce a more intense flavor profile as compared to that of natural cheeses. Hence they may be used at a lower level to impart the same flavor. However, EMC although having a strong flavor profile, do not mimic the textural properties of natural cheeses. EMC have approximately a 15-30 fold more intense flavor and are available as pastes or spray-dried powders. EMC find use in processed foods to give a cheesy flavor or to improve the flavor of a comparatively bland cheese product.

The cheese flavor is a result of the proteolytic, glycolytic and lipolytic pathways. While manufacturing EMC these pathways are only followed, the only difference being the use of enzymes rather than the entire culture micro-organism. The culture technique developed when a certain gentleman mixed curd slurry with NaCl in the ratio 2:1 and blended it. He then incorporated enzymes into it and kept the mixtures at 30 C for 4-5 days with constant agitation. A liquid cheese product with characteristic Cheddar, Brick or Romano flavor could be produced from fresh curd in 4-5 days. Nowadays, either of the following two approaches to manufacturing EMC may be taken. Either the hydrolysis of fat and protein occur simultaneously in one step or each of the hydrolysis is carried out separately and then the end products blended together to give the final EMC product.


EMC flavors available include Cheddar, Mozzarella, Romano, Feta, Parmesan, Blue, Gouda, Swiss, Colby and Brick. These cheese flavors find application in cheese analogues, chips, pasta products, salads, ready to eat foods, frozen foods, canned foods and low fat cheese spreads or cheese substitutes.


Reference:

Kieren N. Kilcawley, Martin G. Wilkinson, Patrick F. Fox, Enzyme Modified Cheese, International Dairy Journal, 8, 1998, 1-10.


Monday, 10 February 2014

Wheat Gluten

Gluten is a storage protein found in cereals like triticale, rye, barley; but perhaps the most well known is wheat gluten. Gluten is made up of the monomeric peptide gliadin and the polymeric peptide  glutenin. Some individuals suffer from Celiac disease- an allergic response to gluten. Hence, the advent of “gluten free” claims on many different food products. Wheat gluten is used in many different ways, for both, food and non-food uses.

Bakery: Perhaps the oldest and best known functional use of gluten is in bread making. Although insoluble in water, gluten can bind approximately twice its weight water giving rise to a hydrated viscoelastic mass. This property of gluten helps  hold together the dough used for making bakery products. In addition, owing to its elasticity, gluten can stretch and expand and help trap in the carbon dioxide bubbles generated during fermentation of bread.  

Meat analogues: When subjected to extrusion processing, gluten proteins align to form microfibrils that in turn form a macroscopic fibrous structure. These microfibrils upon hydration swell and give a fleshy appearance to the texturized wheat gluten. The viscoelastic properties of gluten also enable it to be moulded into a desired shape. This property has been harnessed in making meat or sea food replacements. Gluten may be processed and presented as  high value seafood like crab meat. The extrusion process works on gluten to give it the mouth feel and texture of meat.

Condiment: Although gluten is lacking in some essential amino acids like leucine and threonine, it has a high proportion of glutamine. By chemical methods such as deamidation, this glutamine can be converted to glutamic acid. Wheat gluten has thus been used to produce monosodium glutamate or a liquid similar to soy sauce.

Fortification and breakfast cereals: Wheat gluten is used as a low cost additive to fortify flours having low protein content. Even breakfast cereals make use of wheat gluten to increase their protein content and give a characteristic texture to the product. The most notable amongst these is the Kellog’s K cereal which employs wheat gluten as one of its ingredient. Due to its ability to bind water, gluten has been used as a binding agent for fruit purees used as fillings in nutritional fruit bars. It has also been used in producing synthetic cheese and as replacement for sodium caseinate in imitation cheese products.


Non-food uses: Gluten also has many non-food applications such as its use in adhesive bandages, biodegradable materials and edible coatings. Peptides from gluten have also found use in cosmetics. 


Reference:
Day et al, Wheat-gluten uses and Industry needs, Trends in Food Science & Technology, 17 (2006) 82–90